In times of change and transformation, we strive to provide safe and secure electricity in Germany and the Netherlands.

2,345 MW

Gross capacity

5 thermal power plants

Germany & the Netherlands


Electricity generated in 2018

About Us


We are
energy experts

We are a newly formed power-generation company, backed by Riverstone Holdings, one of the largest and most experienced investors globally in the energy sector, with a dedicated team of power professionals and a 20-year track record of developing durable and innovative energy companies.


We are committed to Europe’s energy transition

We believe that efficient, safely managed thermal power plants will contribute to Europe’s energy transition through the provision of reliable, accessible and affordable power.


Safety and environmental compliance are our highest priorities

We are committed to the safety of the workforce and being a responsible partner in the communities in which we operate. The portfolio of thermal power plants we are acquiring is among the most efficient in Europe and utilizes state-of-the-art technology.


We are focused on operational excellence

Our business will be operated by a workforce that is highly-skilled and determined to deliver best-in-class operational performance, while keeping up with high safety standards.


We have a
long-term vision

We are determined to grow and adapt our business to meet Europe’s future energy challenges. Our partnership with Riverstone Holdings, an investor with expertise across the entire value chain of the energy industry, makes us ideally suited to achieving this goal.


The Onyx management team consists of experienced executives and industry experts.

Ton Duijn

Ton Duijn

COO (Chief Operating Officer)

Former Asset Manager at Vattenfall in the Business Area Heat in Sweden, Germany and the Netherlands


Dr Peter Feldhaus

Chief Executive Officer (CEO)

Former CEO of business area Industrial Solutions of ThyssenKrupp AG and Senior Partner at McKinsey & Company


Dr Dirk Mausbeck

Chief Commercial Officer (CCO)

Former COO at Energie, Baden-Württemberg AG (EnBW) and CEO of Danske Commodities


Frankfurt, 30 November 2019

Riverstone Holdings LLC has completed the acquisition of ENGIE S.A.’s five coal-and biomass-fired power plants in Germany and the Netherlands

On 30 November 2019, Riverstone Holdings LLC (“Riverstone”), via its newly formed power-generation company Onyx, completed the acquisition of ENGIE S.A.’s coal- and biomass-fired power plants in Germany and the Netherlands.

Upon completion of the transaction, Onyx operates five plants comprising approximately 2,350 megawatts of gross installed capacity across sites at Wilhelmshaven, Zolling, Farge and Rotterdam (NL). This portfolio includes two of Europe’s most recently constructed thermal plants, which benefit from high efficiencies, substantial environmental controls, very low emissions profiles and the potential use of sustainable biomass. As a provider of reliable and safe power supplies, Onyx will contribute to energy security and grid stability, thus performing a critical role in enabling Europe’s energy transition.

Onyx is backed by Riverstone, one of the largest and most experienced investors in the energy sector globally. Riverstone has a strong track record of safely and profitably managing power generation assets, with over 29 gigawatts of capacity owned or developed, spanning every major deregulated power market and generation type.

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